Correct answer: Kf61...O-O 2.Ngf7# 1.Kd6?? (2.Qc8#) 1...Kd8 2.Nef7#/Nc6#/Qd7# 1...O-O 2.Ngf7# but 1...Kf8! 1.Qb4?? (2.Qe7#) but 1...Kd8!
